Do I need to enable some vlan-interface on my OpenBSD machine for it to act as a client, with specific settings and stuff, or can I just activate 802.1q on the switch and assign different ports to different vlans, configuring the ip-addresses accordingly, and it'll just plain work?

If my onboard 100Mb NIC understands those tags at all that is...dont know how to check, its onboard on a Via Mini-ITX.

EDIT: Or probably I can just set the switch to strip the tags before sending the frames out the port directly to the client.....right?
They only do good if being send through another hub/switch where the tag needs to remain.
That way the NIC wont have to care a bit about VLAN's, or even know they exist. Right?